Roof Deck is open to Oriole Park ticket-holders at every game, a fact that seemed to impress even a Baltimore City police officer, who was overhead expressing his approval of the covered center-field bar and viewing platform. Variations of the Roof Deck have become popular mixing areas in other stadiums, especially for restless fans who want to keep half an eye on the game as they move around the park.

Resplendent in an orange-and-black boa, The 31-year-old Santos ordered an $8 beer to clinch the deal. Santos said he plans to attend about 60 games at Camden Yards this season, and another 40 or so in other ball parks, major and minor. "I bleed orange," Santos told Doug Duennes, the Orioles' vice president of business operations, who seemed charmed by Santos' enthusiastic reaction to the new Camden Yard amenity.

"Can I bottle you up and take you around?" Duennes asked Santos. He may not need to. Other fans seemed impressed, too, with both the commanding views and the cool lounge seating.

"It's great, spectacular," said Garry Wilcox of Jarrettsville. Wilcox and his friends had just claimed front-row stools on the new Roof Deck at Camden Yards. They still had just about three hours to go until the First Pitch of the 2012 season, but they weren't planning on leaving.

Other than first-come, first-serve, there are no official rules governing the limited seating on the Roof Deck. But what happens if you want to stretch the old legs -- is your seat still yours? Danny Black of Baltimore said that he'd been several times to a similar set-up at Fenway Park and had never seen any tussles for seats.

By 1:30 p.m., there were lines forming at the bottom of the stairs leading up to the Roof Deck, which has reached its capacity.

Just below the Roof Deck, fans were lining up for Gino's Giants and Stuggy's hot dogs. Both concessions were making their Camden Yards debut on Opening Day, and each one was serving a yard-only specialty. Stuart and Ryan Perlberg, the owners of Stuggy's, a Fells Point hot dog shop, were checking out the reaction to the Camden Dog, a hot dog topped with crab mac-and-cheese. Fans at Gino's were tempted by the Camden Giant, a burger-and-crabcake combo that will be sold exclusively at Camden Yards.

Other Opening Day visitors found their way into Dempsey's Brew Pub and Restaurant, which was serving a limited tasting menu. The full menu, the Orioles say, will be avaiilable as soon as the second homestand.

Elsewhere, fans were checking out a revamped center-field picnic area and the new improved sightlines fom the Flag Court. The new facilities and concessions are part of improvements the Orioles made to Camden Yards for the 20th Anniversary season at the Downtown stadium.

But it was the Roof Deck that was making the biggest impression on Opening Day.

On Saturday night, I walked down to Camden Yards and bought a $10 Upper Reserved ticket. At some point, it became less $10 ticket and more like a $10 cover charge, the price for admission to a gorgeous urban gathering place and to the new Roof Deck in particular.

Over the past several years, Baltimore's bar food has steadily improved, with sophisticated flavors and techniques along with a farm-to-table ethos. But what about post-bar food? When the evening's winding down and you realize you're ravenous, the culinary choices are often just not that great.